Waste Water Discharges
Sewage and other liquid wastes that are placed into sewer systems are referred to as “ discharges .” Federal , state and local regulations govern waste water discharges into public sewer systems . In addition to ordinary sewage , waste water discharges from dental offices may include chemicals or metals that are subject to regulation . Chemical waste water discharges may include such wastes as :
• straight alcohol
• ether
• peroxide
• solvents
• X-ray fixer solution
Metals contained in waste water discharges may include such wastes as silver from X-ray fixer solution , amalgam and metals from patient rinse waters .
Waste water discharges containing chemicals or metals are a concern for regulatory agencies because they may interfere with sewage treatment plant operations , or pass through the treatment plant and are deposited in waterways and soils . Metals are known to pass through sewage treatment plants , and sewage treatment plants have established limits of metals permissible in their effluent and sludge .
Local requirements vary . Contact your local sewage treatment plant ( also referred to as a Publicly Owned Treatment Works , or POTW ) to determine what materials may be poured down the drain . If the POTW has a pretreatment program , some potentially hazardous materials may be accepted by the POTW , but prior approval is always necessary .
Federal regulations regarding amalgam separators also prohibit the flushing of waste amalgam and oxidizing or acidic cleaners to be discharged into a POTW .
Dental offices that use a private sewage or septic system should not discharge waste waters containing potentially hazardous materials to their system . Discharge of such wastes to the environment may harm soils , groundwater and other bodies of water .
PDA Waste Management Guidelines 6